[SOLVED] Simple FSK circuit - Where to start with

Status
Not open for further replies.
T

thanhFF

Junior Member level 2
Joined
May 14, 2010
Messages
22
Helped
1
Reputation
2
Reaction score
1
Trophy points
1,283
Location
australia
Activity points
1,451
Hi all,

I am doing a project to design and simulate a transmission circuit. The core of the circuit if a Colpitts Oscillator and a FSK modulator. The osc frequency is 30 Mhz. I am reading abt Oscillator, many documents abt that. But FSK very hard to find. I wanna get a simple circuit to start with. My question is Can we use CMOS transistors to make a FSK modulator(simple one), I saw on the net there are a lot of diagrams abt FSK but in block type, some using matlab to model FSK, some use PLLs..... I am very new with RF so got a lot of troubles at the beginning.

Any suggestions for me to start with this problem. Ah i am using Cadence SpectreRF to simulate.

Tks
 

FSK is digitally modulated frequency modulation..nothing else..
But modulating signal can be filtered before applying to reduce the spectrum explosion..
If you design a VCO, you may apply digital information signal directly or through a filter to Vtune input with appropriate DC voltage to shift the center frequency..
You may also use a PLL and change your Ref signal. etc..
There are many methods..
 
Start with high level simulation by using Simulink block then go to ckt level is my opinion.
 
You can use the schematic below to generate two FSK datarates.

 

Tks all for replying me. Be honest, my knowledge in this are very narrow. Coz the courses i studying based on CMOS technology. So i just wanna make simple circuitry based on that also. But it seems that not easy like I thought. How about this? If i wanna build a simple FSK, which sub-circuits I should look at, and do research about.I am not using Simulink just Cadence only, is it possible?
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…